Technical Field
The invention relates to bioresorbable drug-eluting biopolymer suture-free blood vessel anastomosis devices and methods and systems for facilitating vascular anastomosis. Specifically, the invention is directed to devices that can facilitate vascular anastomosis by providing a quick mechanical union without the need for suturing or tying knots. The bioresorbable biopolymer can include silk fibroin, e.g., silk fibroin and blend that includes silk fibroin, e.g., silk fibroin materials.
Description of Certain Art
Manual suturing is the standard as a technique that necessitates precise placement of sutures in the wall of blood vessels to approximate their ends [4-7]. Current microsurgical suturing techniques involve using fine (8-0 to 12-0) monofilament nylon sutures mounted on sharp round needles. Vessels are prepared under a microscope; vessels may be placed on a double approximating clamp so that the ends can be approximated under no tension [16,22].
Vessel couplers can enable the anastomosis of small diameter vessels in cardiothoracic, vascular, and transplant surgery as well as for microsurgical reconstructive procedures in plastic surgery. Manual suturing requires extreme technical precision to prevent long-term failure from foreign body reaction to the suture material and intimal hyperplasia [4-7]. These factors and others have contributed to persistent failure rates in 2-6% of cases [8,9]. Sutured anastomosis may be unreliable in small (<1.0 mm) or diseased vessels with a tendency to fracture and develop clot, as a contraindication to neovascularization. Furthermore, vascular grafts continue to undergo thrombosis resulting in vascular occlusion, prolonged hospital stays and death [10-15]. Even in experienced hands, microvascular anastomosis remains a challenging and time consuming procedure and has a steep learning curve for any surgeon in training. Reconstitution of blood supply via vessel anastomosis is technically challenging and requires expertise in meticulous microsuturing technique. Technical suturing errors such as uneven spacing, inversion of suture walls, and misalignment of the vessel intima can lead to anastomotic leaks and thrombosis which can be disastrous. For these reasons, alternatives to traditional sutured microvascular anastomosis have been actively investigated [16]. Different devices such as microclips, staples or magnets have been used in an attempt to overcome the technical difficulties of sutures (most of them have been designed for large-caliber vessels greater than 2 mm in diameter) but have been found to be traumatic to blood vessels resulting in failure rates comparable to or higher than those of sutured anastomosis [17-21]. Sutureless vascular anastomosis is a technique gaining interest for decreasing operative time and complexity [21].